This invention relates generally to dispensing closures for hand-held dispensers, and more particularly to devices of the type incorporating a captive closure cap which is hingedly connected to a tubular cap body.
In the past, a number of different closure constructions have been proposed and produced. With most prior arrangements, a number of problems arose, especially after extended periods of use, and with certain types of liquid or cream products. In almost all prior devices, there was a likelihood of the product accumulating in the vicinity of the discharge opening, especially after the first few dispensing operations. While the accumulation from one or two uses was generally only moderate, the product or residue hardened in time, tending to diminish the size of the discharge opening, or even completely blocking off the same. Even where blockage did not occur, a general deterioration of the dispensing function occurred. As the initial residue hardened, additional product would tend to adhere to the hardened material, thereafter solidifying, and making the degree of build-up even worse.
In some prior constructions, product build-up in the vicinity of a discharge opening has been minimized by incorporating a sealing plug in the closure cap, the plug functioning to dislodge any residue before it hardened. A typical cap is shown in U.S. Pat. No. 3,927,805 dated Dec. 23, 1975.
One of the problems with such a plug involved choosing a size which was sufficiently large so as to properly seal the discharge opening, while at the same time not causing undue restriction of movement of the closure cap between the assembled and discharge positions. In the case of a hinged closure cap, there has clearly existed a problem in that with a relatively short hinge, the axis of the closure cap was skewed with respect to the axis of the body at the time that there occurred engagement of the two parts. Accordingly, a pin on the underside of the closure cap had to enter the discharge opening at a substantial angle. If the proposed design was such that the pin diameter was only slightly less than that of the discharge opening, interference would result from such an angled entry. On the other hand, with a significantly smaller pin diameter, the adequacy of the seal was sometimes jeopardized.
In addition, with other types of hinged closures, it was difficult or awkward for the consumer to re-close the container, especially in the presence of dried or hardened product residue. Under such circumstances, the closure cap might not properly seat on the body, thus defeating the closure function of the dispenser.
Still other prior designs have suffered from poor sealing characteristics, resulting in leakage of the product during storage or shipping. In addition, with some prior constructions it was not possible to dispense the last remaining portions of the product, especially where relatively viscous liquids or creams were being used. This, of course, represented unnecessary waste and added expense to the consumer.